Cause of Electricity Disruption on 18 September 2018

Mr Liang Eng Hwa asked the Minister for Trade and Industry (a) what is the root cause of the major disruption to power supply in Singapore on 18 September 2018; and (b) what are the follow-up actions and measures that will be put in place to minimise the risks of recurrence.

Assoc Prof Daniel Goh Pei Siong asked the Minister for Trade and Industry what caused the power failure on 18 September 2018 and how many homes were affected by the blackout.

Ms Rahayu Mahzam asked the Minister for Trade and Industry (a) what are the findings from the investigations by the Energy Market Authority on the disruption of power supply that occurred on 18 September 2018; (b) what are the safeguards that are in place to ensure that there are no power disruptions to critical services, such as those in hospitals, lifts, street lights and traffic lights; and (c) what are the safeguards that can be put in place to prevent another similar occurrence of disruption of power supply in the future.

Mr Speaker, let me begin by tracing the timeline of events behind the electricity supply disruption on 18 September.

That evening, a total of 16 generating units were operating. At 1.17 am, a power generating unit at Sembcorp Cogen Pte Ltd tripped. Based on the Energy Market Authority's (EMA's) preliminary investigations, this was likely due to an equipment fault. This triggered an automatic response by the other 15 units that were running, to increase their supply, to meet the demand for power. This is usually not a problem, as each of the remaining units only had to increase their supply by about 5%. However, a unit at Senoko Energy Pte Ltd tripped a few seconds later, due to failure of a different equipment component. This led to a further shortfall in supply from the operating plants to meet demand, which caused the protection devices in the power system to kick in as designed and automatically disconnected electricity to about 146,500 consumers to rebalance the system. Out of these 146,500 consumers who were affected, 130,535 were households.

To restore electricity supply, EMA immediately instructed other stand-by generating units, including unaffected units from Senoko and YTL PowerSeraya Pte Ltd to provide additional electricity supply. Once these additional units came online after about 15 minutes, electricity supply was progressively restored. While power was fully restored within 38 minutes, some consumers remained affected as the electrical equipment within their premises had to be manually reset.

EMA treats its mandate of ensuring the reliability of Singapore's electricity supply very seriously and has taken the following steps in response to this incident.

Firstly, EMA has been working closely with the two generation companies and their original equipment manufacturers (OEMs) to establish the root cause of their respective equipment failures, even though the units were maintained in accordance with the manufacturers' recommendations. This is an important point because the generation technology is also used in other generating units in Singapore as well as globally, and what happened here could well happen elsewhere. This will take some time, as the parts have to be sent for testing overseas, but we believe a thorough investigation is important.

Secondly, EMA is also working with the industry to review its processes for handling such events to ensure they remain satisfactory. As explained earlier, the technical processes kicked in as designed, allowing for the relatively quick restoration of power. During the blackout, SP Group officers were immediately activated and deployed at key substations and control centres. SP Group also provided the public with progressive updates on its social media channels and concurrently informed the media of its updates. Nonetheless, we will review this incident carefully to see how we can further improve our responses.

Thirdly, we are reviewing our system to ensure that we continue to have sufficient capacity and contingency measures to handle any similar incidents in future. Mr Speaker, I would like to reassure Members of the House that we do, currently, have enough spare capacity in our system, as evidenced by the quick progressive restoration of power within 15 minutes of the incident. In the design of any electricity grid system, we have to balance redundancy and assurance with the cost that will be imposed on consumers. The higher the degree of redundancy, the smaller the probability of disruption, but the higher the cost at the system level.

Hence, we have adopted a calibrated approach in our system planning, with a certain level of redundancy at national grid level, coupled with a higher level of redundancy at the local level for critical systems. This system design has served us well so far, with Singapore having one of the most reliable and affordable electricity systems in the world. From financial year (FY) 2013 to FY2017, the average disruption per consumer annually in Singapore ranged from 12 to 45 seconds, while, in comparison, major cities, such as Tokyo, New York, Hong Kong and London, experienced an average disruption per consumer of between four and 34 minutes in 2015.

The reliability of electricity supply has also not been affected by the liberalisation of the electricity market. In fact, our electricity sector relies on both regulatory powers and market incentives to keep generation companies on their toes. Generation companies that do not maintain their sets will lose market share and face regulatory action by EMA. In addition to the generation companies, EMA also regulates the infrastructure planning and maintenance regime of SP PowerGrid, the national grid operator, to improve system reliability and to minimise disruptions.

For critical services and infrastructure, such as lifts, traffic signalling systems and public hospitals, these have contingency plans to deal with power outages on the national grid. For instance, public hospitals are provided with dual supply sources, each of which is able to provide backup to the hospital if the other one fails. In addition, if there is any disruption from the main power source, backup power systems, such as diesel generators and Uninterrupted Power Supplies (UPS) systems, would automatically kick in, to support all critical equipment and critical facilities. Hospitals also carry out regular and preventive maintenance to ensure that both their electrical installations and backup power systems are in good working condition. During the power outage on 18 September, hospitals in the affected areas activated their backup power supply immediately, preventing disruptions to their operations and patient care. Telecommunication exchanges, similarly, did not experience any disruption as their backup power supplies were activated.

On the other hand, passenger lifts have to be installed with an Automatic Rescue Device that will park the lift at the nearest floor and open its doors during a power failure. Furthermore, a standby generator is required for lifts in very high-rise residential buildings or those serving both residential and commercial and non-residential uses, which will provide emergency power to resume at least one of the lifts. As for traffic signals, the Land Transport Authority (LTA) will work with the Traffic Police to quickly deploy resources where needed during a power outage, to assist with traffic control at affected junctions. Backup generators can also be deployed onsite to provide temporary power supply to mitigate the impact on traffic signal operations.

Beyond these sector-specific measures, EMA has been looking at how technological solutions, such as energy storage systems, can increase security and resilience at the systems level. Such technologies can also address other issues, such as the increased intermittency faced by greater deployment of intermittent generation sources, such as solar power. EMA recently completed a round of industry consultation on the regulatory framework for energy storage systems and will publish a policy paper to provide clarity on the regulatory framework by the fourth quarter of 2018.

We will ensure that we incorporate all the lessons from this incident to ensure continued high standards of reliability for our power systems.

From the Senior Minister of State's reply, it seems that the originating cause of the power supply disruption on 18 September is due to the trip in SembCorp Cogen's generating units. So, can I ask the Senior Minister of State whether such trips do occur quite often to other generation companies (gencos) as well and whether EMA sees power trips at gencos as a potential weak link that needs to be addressed?

Secondly, can I also ask whether EMA carries out audit checks on gencos, including unnotified ones, to ensure that they do carry out their contractual obligations and that the regime is strictly followed?

Mr Speaker, I would say that EMA is currently investigating this incident, together with the gencos and their original equipment manufacturers. So, I would not jump the gun to draw any conclusion until the investigations are completed. But that said, we will not hesitate to take any regulatory actions against SembCorb or Senoko if they are found to be at fault, including imposing a financial penalty under section 14 of the Electricity Act, which is a financial penalty of up to 10% of the licensee's annual turnover or $1 million, whichever is higher; and also requiring the gencos to tighten their standard operating procedures (SOPs), where necessary. So, let us wait for the investigations to be completed.

As to the Member's other question about whether EMA does spot checks to keep the gencos on their toes, the answer is yes, because maintenance works by the gencos are done by the original equipment manufacturers, which the gencos have to pay for. And EMA tracks when the units are shut down, because before they can shut the units down for maintenance, they have to apply to get approval from EMA for shutting down their operations. So, because of the need for them to notify us, we then have a few things that we can do.

First, we would know whether they are doing maintenance, because they have to apply for permit to do so. Secondly, we also send our EMA teams down to do spot checks when they are doing their maintenance to ensure that actual work is done. And when the maintenance is done, EMA staff would then file a report highlighting any issues and any problems that need to be resolved, and what are the recommendations for resolving them. Third, we also do a spot check to audit their spare inventory, so we know if there are shortfalls in any of these areas that need to be ramped up.

What we also do is we use a regulatory framework to ensure that standards are maintained, by first imposing penalties if they are not well maintained and, secondly, to give them some of these regulatory incentives to ensure that they are kept on their toes. Because these companies would lose revenue if they cannot fulfil their maintenance requirements and, therefore, they will lose revenue and they will not be able to fulfil their contractual requirements when the units fail.

Secondly, the warranties will become invalid if it is not maintained according to the OEM's requirements. So, there are sufficient incentives to ensure that these companies keep the maintenance up to par, in accordance with the guidelines.

I have three questions. The first question is: during this interim period where the equipment fault is being investigated, are there any safeguards being put in place to prevent recurrences of equipment failure? The second question is: was there any link to consumer behaviour, especially extensive use of air-conditioners by residential households, due to hot weather, for example? So, is there any link in the disruption to this consumer behaviour? And the third question is: is the grid resilient enough to meet changing consumer behaviour because of climate change and other trends?

Mr Speaker, before the investigation is concluded, it would not be wise to kneejerk and impose more demands on the system unnecessarily. Suffice to say that we have enough spare capacity in the number of generators that we have to meet consumer demand. Certainly, the trip on that night was not due to excessive consumer demand, but due to equipment fault. With the OEMs now looking at the equipment, and with the equipment being sent for overseas testing, let us give it some time for things to settle. Nonetheless, EMA is exploring and also looking at it with all the gencos to see how we can strengthen our processes and our SOPs, where necessary.